This invention relates generally to apparatus for separating particles from dirty liquid and, more particularly, to a magnetic separator of the type commonly used to clean machine tool coolant by magnetically removing entrained metal chips and fine particles from the coolant.
In such a separator, dirty liquid is delivered to a flow path defined in part by a curved apron extending around the lower side of a rotatable drum having a magnetic outer surface. As the liquid flows to and around the drum, the particles are magnetically attracted to the drum and thus are removed from the liquid. The drum is slowly rotated to raise the collected particles out of the flow path and to enable the particles to be scraped from the drum.
In many prior magnetic separators, a change in the flow rate of the dirty liquid supplied to the drum can result in a change of the level of liquid in contact with the drum. If the incoming flow rate is extremely low, the degree of contact between the liquid and the drum may not be sufficient to effect good separation. If the flow rate is extremely high the drum may not be capable of handling the flow and may cause an overflow. It has, therefore, been necessary in many cases to adjust the separator, either manually or with a relatively complex control system, in an effort to correlate the flow past the drum with the incoming flow rate and to keep a substantially constant level of liquid in contact with the drum.